Impacting device for releasing blocked objects by impact

ABSTRACT

An impacting device is capable of being used in an impact hammer and/or a drill for releasing by impact tools blocked in rocks. An impact impetus supplied by an impact piston is modified via an impact-deflecting device having a sliding lever and a deflecting lever, such that the impact is carried out in a releasing impact direction opposite the normal impact direction and is transmitted to a tool by a slide and a locking lever. The tool is released after a few strokes produced by the impact piston. The impact device is suitable for both unilateral air springs and double air springs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a percussion apparatus according to thepreamble of patent claim 1. The invention relates in particular to apercussion apparatus which can be used in an impact hammer and/or drillhammer.

When work is done using impact and drill hammers, the situation oftenarises where the tool, e.g. a cutter or a bit, wedges or jams in therock. While a practiced operator can usually still prevent the tool fromjamming during drilling with the drill hammer, it is not alwayspossible, during demolition work using a large impact hammer, even forthe expert to avoid wedging or jamming of the cutter. It is usuallydifficult to release a wedged tool because this can only be accomplishedby using a second cutter, in the case of a certain hammer design only byusing a second hammer, to release the jammed tool by impact. During theimpact-release of a jammed bit, the effort necessary for this purpose isusually particularly high since the drill is already lodged deep in therock and it is thus necessary to cut away all the rock around the drillhole. In any case, the impact-release of a jammed tool requiresconsiderable outlay in terms of time and equipment.

2. Description of the Related Art

U.S. Pat. No. 5,485,887 discloses a percussion apparatus having animpact-generating device which has an axially reciprocating percussionpiston. In an operating state, a tool can be forced in anoperational-impact direction by the percussion piston while, in animpact-release state, a blow of the percussion piston can be transmittedto the tool such that said tool can be forced in an impact-releasedirection, which is counter to the operational-impact direction. Thereversal of the impact direction is achieved purely pneumatically by thedisplacement of an outer piston, which encloses the percussion piston.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the invention is to specify a percussion apparatus bymeans of which the impact-release of a jammed tool can be carried out ina straightforward and time-saving manner.

The object is achieved according to the invention by a percussionapparatus having the features of patent claim 1. Advantageous furtherdevelopments of the invention are defined in the subclaims. Such apercussion apparatus can be used particularly advantageously in animpact hammer and/or drill hammer.

The invention relates to a percussion apparatus having animpact-generating device which has an axially reciprocating percussionpiston, it being possible, in an operating state, for a tool to beforced in an operational-impact direction by the percussion piston,wherein, in an impact-release state, a blow of the percussion piston canbe transmitted to the tool via an impact-converting device such thatsaid tool can be forced in an impact-release direction, which is counterto the operational-impact direction.

The invention thus provides a percussion apparatus in which the impactenergy of the percussion piston, which belongs to the impact-generatingdevice, can be utilized for releasing the jammed tool from the rockagain by impact, in that said tool is forced in a direction which isdirected counter to the normal impact direction. The percussion pistonusually strikes against the tool, in the operational-impact direction,directly or via an interposed riveting set. The impact-converting devicemakes it possible to pick up the movement of the percussion pistoneither in the operational-impact direction or in the impact-releasedirection and supply it to the tool in the form of a blow in theimpact-release direction.

Particularly advantageous is an embodiment of the invention in which theblow is transmitted, and has its direction deflected, via theimpact-converting device when the percussion piston forces theimpact-converting device in the operational-impact direction. Thepercussion piston is usually designed such that it can absorb thegreatest loading in the operational-impact direction, because it strikesagainst the tool during movement in this direction. This means that itcan also withstand the loading necessary for the impact-release since,in this case, the forces and blows which are necessary tend to besmaller than in the operating state. For the further development of thepercussion apparatus according to the invention, it is not necessary fora conventional percussion apparatus to be newly designed in terms ofimpact geometry and strength. Rather, the solution according to theinvention can be achieved by the impact-converting device being added.

A particularly advantageous further development of the invention isdefined in that the impact-converting device has an impact-deflectingdevice and an impact-transmission device; the impact-deflecting devicehas a deflecting lever which can be pivoted about a rotary pin, can beforced in the operational-impact direction at a first lever end by thepercussion piston and is coupled to the impact-transmission device at asecond lever end, which is located opposite in relation to the rotarypin and, accordingly, can be moved in the impact-release direction; andthe impact-transmission device has a slide which can be moved in theimpact-release direction as well as a tool locking mechanism which isfastened on the slide and transmits the blow to the tool.

The impact-deflecting device serves for picking up the blow which isdelivered by the percussion piston and directed in theoperational-impact direction and for deflecting said blow into a blowwhich is directed in the opposite, impact-release direction. Thedeflected blow is transmitted to the tool by the impact-transmissiondevice, and the tool can then be released by impact.

The percussion piston moving in the operational-impact direction canadvantageously act directly on the deflecting lever, which belongs tothe impact-deflecting device.

Alternatively to this, the impact-deflecting device has, between thepercussion piston and the deflecting lever, a sliding lever which can bedisplaced between an operating position and an impact-release position,can be pivoted about one of its ends and via which the percussion-pistonblow in the operational-impact direction can be transmitted to thedeflecting lever. On the one hand, the sliding lever permits the blow tobe transmitted from the percussion piston to the deflecting lever with ageometry which is particularly advantageous in terms of the forcetransmission. In addition, the sliding lever can be displaced betweenthe operating position and the impact-release position and thus servesas a changeover means between the operating state and the impact-releasestate, which the operator can select freely by adjusting the slidinglever.

In a preferred embodiment of the invention, the impact-generating devicehas a percussion mechanism with a pneumatic spring acting on one side.Said percussion mechanism, which is known per se, has the advantage ofbeing very robust and straightforward to construct and has proven to bevery successful in practice. Without any change in the design of thepercussion mechanism being necessary, the percussion apparatus can besupplemented in the manner according to the invention by virtue of theabovedescribed features being added.

In another embodiment of the invention, the blow is transmitted via theimpact-converting device when the percussion piston forces theimpact-converting device in the impact-release direction. In this case,the percussion piston—in contrast to the embodiments described above—isalready moving in the direction in which the tool is to be released byimpact. This has the advantage that there is no need for anyimpact-deflecting device.

Rather, a particularly advantageous embodiment is defined in that theimpact-converting device has an impact-transmission device; theimpact-transmission device can be forced in the impact-release directionby the percussion piston and transmits the blow to a point which islocated at the tool-receiving means; and fastened on theimpact-transmission device is a tool locking mechanism which transmitsthe blow to the tool.

This arrangement makes it possible for the impact energy to be picked upfrom the percussion piston already moving in the impact-releasedirection and supplied to the tool, which is arranged in the oppositedirection, in order to release said tool by impact.

It is particularly advantageous in this embodiment if, at a point whichis located behind the percussion piston, as seen in theoperational-impact direction, the impact-transmission device can beforced in the impact-release direction by the percussion piston when thepercussion piston moves in the impact-release direction.

Quite particularly advantageous is an embodiment in which theimpact-generating device has a percussion mechanism with a double-actingpneumatic spring. Such double pneumatic springs are known per se andhave the advantage of starting reliably from a standstill and of notunduly stressing the material. Since, in the case of a pneumatic springwhich acts on two sides, the percussion piston also moves in theimpact-release direction in a defined manner, it is possible for theimpact energy of said percussion piston to be picked up reliably andsupplied to the tool.

It may be advantageous, in the case of all the previously mentionedpercussion apparatuses, for the tool locking mechanism to have a lockinglever which engages behind a collar belonging to the tool. Such alocking lever has usually already been provided in known percussionapparatuses, in order to secure the tool in the apparatus. For thisreason, there is no need for any additional components for transmittingthe impact energy to the tool for impact-release purposes. However, thelocking lever has to be of sufficient dimensions to be able to withstandthe dynamic loading during the impact-release operation.

It is particularly advantageous if the percussion apparatus can bechanged over manually between the operating state and impact-releasestate. As has already been described above in conjunction with thesliding lever, it is thus possible for the operator himself to determineat any time the direction in which the impact action takes place. Manualchangeover is also possible in the case of pneumatic springs which acton two sides and in which a coupling arranged between an electric motorand a crank mechanism, which energizes the pneumatic spring, can beactivated via a control slide. It may be necessary here for the couplingto be bridged mechanically in the idling position, in order for it to bepossible to change the percussion apparatus into the impact-releasestate.

The percussion apparatus according to the invention can be usedparticularly advantageously in an impact hammer and/or drill hammer.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention are describedhereinbelow, by way of preferred embodiments, with the aid of thefigures, in which:

FIG. 1 shows a partial section of a percussion apparatus according tothe invention in the operating state, said percussion apparatus having apneumatic spring which acts on one side;

FIG. 2 shows a partial section of the percussion apparatus according tothe invention in the impact-release state; and

FIG. 3 shows a schematic illustration of another embodiment of thepercussion apparatus according to the invention in the operating state,said percussion apparatus having a double pneumatic spring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a partial section through the percussion apparatus of animpact hammer, and, for reasons of simplicity, elements of animpact-generating device which are known per se has been left out of thepartial section. There are no illustrations, in particular, of anelectric motor, a crank mechanism driven by the electric motor, and adrive piston which can be moved axially by the crank mechanism and canbe moved axially in a hollow-cylindrical recess of a percussion piston1.

The percussion piston 1 is arranged such that it can be moved axially ina housing 2 of the hammer, and it is driven by the drive piston via apneumatic spring formed between the drive piston and a closed end side 3of the percussion piston 1. The percussion piston 1 thus follows theforced movement of the drive piston, which is coupled to the crankmechanism.

Whenever the percussion piston 1 reaches the extreme position shown inFIG. 1, in which the drive piston has driven it forward as far aspossible (downward in FIG. 1), it strikes against a tool 4. The tool 4,for example a cutter, is inserted into the hammer and has a collar 5which is secured via a locking lever 6. A spring (not illustrated) actson the locking lever 6, with the result that a nose 7 always engagesbehind the collar 5 and retains the tool 4 in the housing 2. It is onlywhen the locking lever 6 is actuated by the operator that the nose 7 canbe pivoted out of the movement path of the collar 5 and the tool 4 canbe removed from the hammer. This arrangement is known per se and willtherefore not be discussed in any more detail here.

FIG. 2 shows an essentially similar section, in which the tool 4 is inthe idling position and has slid out of the housing 2 to the extentwhere the collar 5 rests on the nose 7 of the locking lever 6.

In the idling position, which is shown in FIG. 2, it is no longerpossible for the percussion piston 1 to reach the tool 4, with theresult that it is no longer possible for any blow to be transmitted tothe tool 4 either. It is only when the tool 4 is positioned on the rockwhich is to be worked that the tool 4 is pushed into the hammer againand reaches the position shown in FIG. 1.

The impact-converting device according to the invention is describedhereinbelow.

In this embodiment, the impact-converting device has animpact-deflecting device for deflecting in the impact-release direction(arrow direction F) the blow which is delivered by the percussion piston1 and is initially directed in the operational-impact direction (arrowdirection B), and it also has an impact-transmission device fortransmitting to the tool 4 the blow which is now directed in theimpact-release direction F.

The impact-deflecting device comprising a sliding lever 8 which isfastened pivotably on a rotary stub 9 at one end and has its other endprojecting out of the housing in the operating position, which is shownin FIG. 1. At the fastening with the stub 9, the sliding lever 8 has aslot 10 and can thus be displaced between the operating position, whichis shown in FIG. 1, and an impact-release position, which is shown inFIG. 2. The positions may be changed in each case by virtue of thesliding lever 8 being pressed from the outside. In the operatingposition, which is shown in FIG. 1, one end of the tool 4 passes througha through-passage opening 11 of the sliding lever 8. The sliding lever 8thus does not function in the operating state.

Arranged beneath the sliding lever 8 is a deflecting lever 12 which isretained approximately centrally in the housing 2 such that it can bepivoted about a rotary stub 13. At its opposite end, the deflectinglever 12 is coupled, by means of a pin 14, to a slide 15 belonging tothe impact-transmission device. Furthermore, on one side of the rotarystub 13, the deflecting lever 12 has a through-passage opening 16through which the end of the tool 4 can be guided without the tool 4 andthe deflecting lever 12 coming into contact with one another.

The slide 15 is arranged such that it can be moved longitudinally in thehousing 2 and, at the end located opposite the pin 14, it bears thelocking lever 6 which is arranged pivotably on the slide 15 and canlikewise be moved longitudinally therewith.

As has already been mentioned, FIG. 2 illustrates a section through thepercussion apparatus according to FIG. 1, the percussion apparatus beinglocated in an impact-release state. For this purpose, the operator hasraised the hammer from the rock which is to be worked, with the resultthat the tool 4 slides into the idling position, which is shown in FIG.2, until such time as it is retained at its collar 5 by the nose 7.

If the operator then realizes that the tool, in this case a cutter forexample, has jammed in the rock, he displaces the sliding lever 8 out ofthe operating position into the impact-release position, which is shownin FIG. 2, as a result of which the through-passage opening 11 alsomoves to the side and, in its place, an impact surface 17 is arrangedbeneath the percussion piston 1.

The percussion piston 1, which is initially in the idling position andmay also have slid some way into the through-passage opening 11, and ofwhich the pneumatic spring is usually likely to have had an airextracted from it, is pushed back by the sliding lever 8, then passesinto the operating position again and strikes against the impact surface17 in the same way as the tool 4 was struck previously.

The blow of the percussion piston 1 is transmitted to the outer end ofthe deflecting lever 12 via a nose 8 a by virtue of the sliding lever 8pivoting about the rotary stub 9. Since the deflecting lever 12 isfastened pivotably on the rotary stub 13, that end of the deflectinglever 12 which is located opposite the point of impact initiationaccordingly moves in the opposite direction with the rotary pin 14, i.e.in the impact-release direction F. The pin 14 carries along the slide 15and thus also the locking lever 6 and the secured collar 5 of the tool4, with the result that the tool 4 is forced in the impact-releasedirection F and is likely to be freed from the clamping state againafter just a small number of blows.

It is obvious that the blow can be transmitted to the impact-deflectingdevice directly from the percussion piston or via an additionalintermediate element. It is likewise obvious that transmission of theimpact energy in the operational-impact direction B can take place fromthe percussion piston 1 either directly to the tool 4 or via aninterposed riveting set (not illustrated).

FIG. 3 schematically shows another embodiment of the invention, in whicha double-acting pneumatic spring is used instead of the pneumatic springwhich acts on one side, from FIGS. 1 and 2.

It is possible to see in FIG. 3 part of a connecting rod 20 which move adrive piston 21 back and forth. A percussion piston 22 follows themovement of the drive piston 21 in a known manner, a pneumatic spring 23being formed respectively in front of and behind the percussion piston22. This is the reason why said pneumatic spring is also referred to asa “double pneumatic spring”.

The percussion piston 22 strikes against a tool 24 in a known manner.Alternatively to this, it is also possible for the percussion piston 22to strike against a riveting set (not illustrated) arranged between thetool 24 and the percussion piston 22.

At its rear end 25, the percussion piston 22 has an extension whichpasses through the drive piston 21 in the rearward direction, as seen inthe operational-impact direction B. Arranged behind the rear end 25 is ahook 26 of a slide 27 serving as an impact-transmission device, and therear end of the percussion piston 22 acts on said hook when thepercussion piston moves in the impact-release direction F. The impactenergy in the impact-release direction F is transmitted to a collar 29of the tool 24 via the hook 26 and the slide 27, via a locking element28 (only illustrated in outline), with the result that the tool 24 canbe released by impact.

When the hammer is raised from the rock, and the percussion apparatusstarts to idle, the tool 24 slides—as has been described above—a certaindistance out of the housing of the hammer. The slide 27 and the lockingelement 28 follow this sliding movement over a defined section andlikewise move out of the housing. This means that the hook 26 passesinto the movement region of the rear end 25 of the percussion piston 22,with the result that the impact energy of the percussion piston 22 maysubsequently be transmitted to the tool 24 via the slide 27.

If the percussion apparatus should be provided with a coupling whichinterrupts the flux of force between the drive and the double pneumaticspring when the tool 24 assumes the idling position, it is, of course,necessary to provide bridging for the coupling or a switch for themanual actuation of the coupling, in order that the pneumatic-springpercussion mechanism can also be made to operate when the tool 24 is inthe idling position.

The collar 29 of the tool 24 does not have to be locked directly by thelocking element 28, which serves essentially for transmitting the impactenergy, in the hammer. Rather, it may be expedient to provide a separatelocking mechanism (not shown in FIG. 3) for the tool 24. In this case,the locking element 28 would serve exclusively for transmitting theimpact energy in the impact-release direction F. The locking of the toolis thus to be regarded rather more as an additional function to theimpact transmission.

What is claimed:
 1. A percussion apparatus comprising: animpact-generating device having an axially reciprocating percussionpiston configured to drive a tool to move in an operational-impactdirection; an impact-converting device which is coupled to said impactgenerating device, which is integrated into said percussion apparatus,and which is switchable between an operational-impact position thereofand an impact-release position thereof, wherein, when theimpact-converting, device is in the impact-release position thereof, ablow of the percussion piston is transmitted to the tool via theimpact-converting device to force the tool in an impact-releasedirection, which is counter to the operational-impact direction, andwherein, when the impact-converting device is in the operational-impactposition thereof, a blow of the percussion piston is transmitted to thetool via the impact-converting device to force the tool in theoperational-impact direction; and a tool locking mechanism which isconfigured to lock the tool to the percussion apparatus and to retainthe tool in its locked configuration when the tool is forced in theimpact-release direction thereof.
 2. The percussion apparatus as claimedin claim 1, wherein the impact-converting device includes animpact-deflecting device and an impact-transmission device; wherein theimpact-deflecting device includes a deflecting lever which is pivotableabout a rotary pin and which is forced in the operational-impactdirection at a first lever end thereof by the percussion piston and iscoupled to an impact-transmission device at a second lever end thereofwhich is located opposite the first lever end; wherein the rotary pin isdisposed between the first lever end and the second lever end; whereinthe second level end is movable in the impact-release direction; whereinthe impact-transmission device has a slide which is movable in theimpact-release direction; and wherein the tool locking mechanismcomprises a portion of the impact-transmission device, is fastened onthe slide and transmits the blow to the tool.
 3. The percussionapparatus as claimed in claim 2, wherein the percussion piston actsdirectly on the deflecting lever when said percussion piston moves inthe operational-impact direction.
 4. The percussion apparatus as claimedin claim 2, wherein the tool locking mechanism includes a locking leverwhich engages behind a collar of the tool.
 5. The percussion apparatusas claimed in claim 1, wherein the impact-generating device includes apercussion mechanism with a pneumatic spring acting on one side.
 6. Thepercussion apparatus as claimed in claim 1, wherein the percussionapparatus can be changed over manually between the operating state andthe impact-release state.
 7. The percussion apparatus as claimed inclaim 1, wherein said percussion apparatus can be used in at least oneof an impact hammer and a drill hammer.
 8. The percussion apparatus asclaimed in claim 1, wherein the impact-converting device is manuallyswitchable between the operational-impact position thereof and theimpact-release position thereof.
 9. The percussion apparatus as claimedin claim 1, wherein the percussion piston is coaxial with the tool bothwhen the tool is driven in the operational-impact direction and in theimpact-release direction.
 10. A percussion apparatus for driving a tool,the percussion apparatus comprising: an impact-generating device havingan axially reciprocating percussion piston, the percussion piston beingmovable in an operational-impact direction to drive a tool to move; animpact-converting device which is coupled to the impact generatingdevice and to the tool, which is integrated into the percussionapparatus, and which is switchable between an operational-impactposition thereof and an impact-release position thereof, wherein, whenthe impact-converting device is in the operational-impact positionthereof, movement of the percussion piston in the operational-impactdirection drives the tool to move in the operational-impact direction,and wherein, when the impact-converting device is in the impact-releaseposition thereof, movement of the percussion piston in theimpact-release direction drives the tool to move in an impact-releasedirection which is counter to the operational-impact direction; and atool locking mechanism which is configured to lock the tool to thepercussion apparatus and to retain the tool in its locked configurationwhen the tool is forced in the impact-release direction thereof.
 11. Thepercussion apparatus as claimed in claim 10, wherein theimpact-converting device is manually switchable between theoperational-impact position thereof and the impact-release positionthereof.
 12. The percussion apparatus as claimed in claim 10, whereinthe percussion piston is coaxial with the tool both when the tool isdriven in the operational-impact direction and in the impact-releasedirection.
 13. A percussion apparatus comprising: an impact-generatingdevice having an axially reciprocating percussion piston configured todrive a tool to move in an operational-impact direction; animpact-converting device which is coupled to said impact generatingdevice and via which a blow of the percussion piston can be transmittedto the tool to force the tool in an impact-release direction that iscounter to the operational-impact direction, wherein the blow istransmitted, and has its direction deflected, through theimpact-converting device when the percussion piston forces the tool inthe operational-impact direction; wherein the impact-converting, deviceincludes an impact-deflecting device and an impact-transmission device;wherein the impact-deflecting device includes a deflecting lever whichis pivotable about a rotary pin and which is forced in theoperational-impact direction at a first lever end thereof by thepercussion piston and is coupled to an impact-transmission device at asecond lever end thereof which is located opposite to the first end,wherein the second lever end of the deflecting lever is movable in theimpact-release direction; wherein the impact-transmission deviceincludes (1) a slide which is movable in the impact-release directionand (2) a locking mechanism which is fastened on the deflecting lever;wherein the impact-deflecting device includes a sliding lever which islocated between the percussion piston and the deflecting lever inoperative communication with the percussion piston and the deflectinglever, which can be displaced between an operating position and animpact-release position, which is pivotable about one of its ends, andvia which a percussion piston blow is transmitted to the deflectinglever to release the tool when the percussion piston moves in theoperational-impact direction thereof and when the sliding lever is inthe impact-release position thereof.